Histopathological changes in the electrical conduction of cardiac nodes after acute myocardial infarction in dogs and horses, compared with findings in humans: A histological, morphometrical, and immunohistochemical study.

Background and Aim: The heart conduction system is responsible for the occurrence of various types of cardiac arrhythmia. This study aimed to histologically and morphometrically describe damaged cardiac nodes during acute myocardial infarction and to compare them with normal tissues in dogs and horses. Materials and Methods: This study describes the morphometry of cardiac nodes in five dogs and five elderly horses that succumbed to sudden cardiac death (SCD). A computerized morphometric study was conducted to determine the number of cells composing the nodes, different shape and size parameters of nodes, and their relationship with degenerative changes due to cardiac conditions. Results: In both species, the sinoatrial node (SAN) was ovoid in shape whereas the atrioventricular node (AVN) was pyramidal in shape. The percentage of collagen fibers inside the SAN of dogs (47%) and horses (50%) was found to be higher than that of cells. In contrast, the percentage of cells in the AVN of dogs (24%) and horses (16%) was higher than that of connective tissues. In the SAN, the area (p = 0.09), maximum diameter (<0.001), and mean diameter (0.003) of P cells were larger in dogs than in horses. Conclusion: Overall, the SAN cells and surrounding cardiomyocytes in dogs and horses as well as the AVN cells in dogs that succumbed to SCD decreased in size compared with those in normal hearts.

Heinrich Ewald Hering's discovery of the heart pacemaker: Hering, Tawara and Aschoff's search for its morphological basis, the sinoatrial node, and why they failed.

Two groups of investigators investigated the heart pacemaker and its morphological basis in the early twentieth century. The first group was formed by Henrich Ewald Hering (physiologist), Sunao Tawara and Ludwig Aschoff (morphologists). The second group was composed of James Mackenzie (general practitioner and clinical investigator), Arthur Keith and Martin Flack (morphologists). These groups were formed almost at the same time in 1903. Their work resulted in the discovery of the atrioventricular node and Purkinje network (Sunao Tawara, in 1906), heart pacemaker (H E Hering, in 1907) and sinoatrial node (Keith and Flack, in 1907). Here, it is shown how the interconnections of the concurrent works of these groups resulted in the discovery not only of the function, but also of the structure of the sinoatrial node.

Noisy stimulation effect in calcium dynamics on cardiac cells.

Noise is present in nature, and it affects the nervous and cardiovascular system. Noise added to stimuli may change the performance of excitable cells. In this paper, we study the effect of noise on the two main heart cell types: pacemaker and myocardial cells. This study investigates whether noise can induce changes in calcium dynamics on the two main heart cell types: pacemaker and myocardial cells, when stimuli with periodic electrical signals are disturbed by Gaussian white noise. Calcium dynamic parameters were obtained using imaging signals. Our results show that low intensities of noise favor amplitude and raise rate calcium dynamics, although our results show that the pacemaker cells are not affected by a noisy stimulus. Altogether, these findings suggest that noise plays a key role in calcium dynamics.

Cardiac arrest induced by muscarinic or adenosine receptors agonists is reversed by DPCPX through double mechanism.

In the right atrium (RA), adenosine and acetylcholine inhibit the pacemaker function of the sinoatrial node and induce cardiac arrest. Pre-incubation of receptor antagonists is known to inhibit the cardiac arrest induced by these agonists; however, the effect of antagonist administration after established cardiac arrest has not been described. Therefore, we assessed whether specific receptor antagonists could revert cardiac arrest induced by adenosine and muscarinic receptors activation. RA isolated from adults Wistar rats were mounted in an organ bath containing Krebs solution. Cardiac arrest was induced by adenosine or ATP (1mM), the A1 adenosine receptor agonist CPA (0.1-1µM), and muscarinic receptor agonists, carbachol (0.3-1µM) and acetylcholine (1mM). After establishing the cardiac arrest, the A1 adenosine receptor antagonist DPCPX (0.3-30µM), the muscarinic receptor antagonist atropine (10nM to 100µM) or the phosphodiesterase inhibitor IBMX (10-300µM) were incubated in order to check for the return of spontaneous contractions. DPCPX reversed the cardiac arrest induced by adenosine, ATP and CPA. In addition, atropine reversed the cardiac arrest induced by carbachol. Unexpectedly, DPCPX also reversed the cardiac arrest induced by carbachol. Similarly to DPCPX, the phosphodiesterase inhibitor IBMX reversed the cardiac arrest induced by adenosine, CPA and carbachol. The antagonism of adenosine and acetylcholine receptors activation, as well as phosphodiesterase inhibition, are able to revert cardiac arrest. DPCPX restore spontaneous contractions via the selective antagonism of A1 adenosine receptor and through a secondary mechanism likely related to phosphodiesterase inhibition.

Variação nos tipos de irrigação do nodo sinoatrial em cães de diferentes raças / Variation in irrigation of the sinoatrial node in dogs of different breeds

Considerando a heterogeneidade anatômica e eletrofisiológica do nodo sinoatrial para a geração e propagação do potencial de ação, bem como as particularidades relacionadas a origem da sua irrigação sanguínea, este trabalho teve como objetivo analisar o comportamento das artérias envolvidas na irrigação do nodo sinoatrial em cães realizando uma análise descritiva e comparativa entre diferentes raças estudadas, detalhando a origem, o percurso e a ramescência dos vasos, assim como a eventual ocorrência de anastomoses. Ao todo analisamos resultados obtidos em 240 corações, os quais foram fixados em solução de formalina 10% e submetidos a diafanização de Spalteholz. A irrigação deste ocorre mediante colaterais oriundos do ramo circunflexo direito ou ramo circunflexo esquerdo, mostrando particularidades diferentes para cada raça. Assim, predominantemente, nas raças ora estudadas a irrigação arterial do nodo sinoatrial depende exclusivamente (63,6%), ou de anastomoses de colaterais da artéria coronária direita, havendo também participação dos ramo proximal atrial direito e intermédio atrial direito. Menos frequentemente (15,4%) o suprimento sanguíneo ocorre exclusivamente por conta do ramo proximal atrial esquerdo, oriundo do ramo circunflexo da artéria coronária esquerda. Os dados aqui apresentados sobre a origem da irrigação sanguínea do nodo sinoatrial e a ramescência dos vasos envolvidos nesta tarefa representam conhecimento fundamental para o desenvolvimento da clínica-cirúrgica em cães, da patologia e trabalhos de natureza experimental.(AU)

Considering the anatomical and electrophysiological heterogeneity of the sinoatrial node for generation and propagation of the action potential, as well as the particularities relating to the origin of blood nutrition, this study aimed to analyze the behavior of arteries involved in irrigation of the sinoatrial node in dogs performing a descriptive and comparative analysis between different breeds, with emphasis in the origin, pathway and branching of vessels, as well as the presence of anastomoses. Totally, 240 hearts were fixed in solution of formalin 10% and subjected to Spalteholz diaphanization. The vascularization of the sinoatrial node occurs by the right circumflex branch or left circumflex branch, showing several particularities according to the breed. Thus, predominantly in the studied breeds, the blood supply of the sinoatrial node depends exclusively (63.6%) or from anastomosis of the right coronary artery. There is also participation of right atrial proximal branch and right atrial intermediary branch. Less often (15.4%) the blood supply occurs exclusively from the left atrial proximal branch, which is a branch of the circumflex branch of the left coronary artery. In summary, our results related to the origin of the sinoatrial node blood nutrition and the branching of vessels involved on that represents a fundamental knowledge for the development and improvement of surgery in dogs, as well as for pathology and experimental research.(AU)

Variação nos tipos de irrigação do nodo sinoatrial em cães de diferentes raças / Variation in irrigation of the sinoatrial node in dogs of different breeds

Considerando a heterogeneidade anatômica e eletrofisiológica do nodo sinoatrial para a geração e propagação do potencial de ação, bem como as particularidades relacionadas a origem da sua irrigação sanguínea, este trabalho teve como objetivo analisar o comportamento das artérias envolvidas na irrigação do nodo sinoatrial em cães realizando uma análise descritiva e comparativa entre diferentes raças estudadas, detalhando a origem, o percurso e a ramescência dos vasos, assim como a eventual ocorrência de anastomoses. Ao todo analisamos resultados obtidos em 240 corações, os quais foram fixados em solução de formalina 10% e submetidos a diafanização de Spalteholz. A irrigação deste ocorre mediante colaterais oriundos do ramo circunflexo direito ou ramo circunflexo esquerdo, mostrando particularidades diferentes para cada raça. Assim, predominantemente, nas raças ora estudadas a irrigação arterial do nodo sinoatrial depende exclusivamente (63,6%), ou de anastomoses de colaterais da artéria coronária direita, havendo também participação dos ramo proximal atrial direito e intermédio atrial direito. Menos frequentemente (15,4%) o suprimento sanguíneo ocorre exclusivamente por conta do ramo proximal atrial esquerdo, oriundo do ramo circunflexo da artéria coronária esquerda. Os dados aqui apresentados sobre a origem da irrigação sanguínea do nodo sinoatrial e a ramescência dos vasos envolvidos nesta tarefa representam conhecimento fundamental para o desenvolvimento da clínica-cirúrgica em cães, da patologia e trabalhos de natureza experimental.(AU)

Considering the anatomical and electrophysiological heterogeneity of the sinoatrial node for generation and propagation of the action potential, as well as the particularities relating to the origin of blood nutrition, this study aimed to analyze the behavior of arteries involved in irrigation of the sinoatrial node in dogs performing a descriptive and comparative analysis between different breeds, with emphasis in the origin, pathway and branching of vessels, as well as the presence of anastomoses. Totally, 240 hearts were fixed in solution of formalin 10% and subjected to Spalteholz diaphanization. The vascularization of the sinoatrial node occurs by the right circumflex branch or left circumflex branch, showing several particularities according to the breed. Thus, predominantly in the studied breeds, the blood supply of the sinoatrial node depends exclusively (63.6%) or from anastomosis of the right coronary artery. There is also participation of right atrial proximal branch and right atrial intermediary branch. Less often (15.4%) the blood supply occurs exclusively from the left atrial proximal branch, which is a branch of the circumflex branch of the left coronary artery. In summary, our results related to the origin of the sinoatrial node blood nutrition and the branching of vessels involved on that represents a fundamental knowledge for the development and improvement of surgery in dogs, as well as for pathology and experimental research.(AU)

Compound Heterozygous SCN5A Mutations in a Toddler - Are they Associated with a More Severe Phenotype? / Heterozigose Composta no Gene SCN5A em Criança - Há Associação com Gravidade da Doença?

Abstract Compound heterozygosity has been described in inherited arrhythmias, and usually associated with a more severe phenotype. Reports of this occurrence in Brugada syndrome patients are still rare. We report a study of genotype-phenotype correlation after the identification of new variants by genetic testing. We describe the case of an affected child with a combination of two different likely pathogenic SCN5A variants, presenting sinus node dysfunction, flutter and atrial fibrillation, prolonged HV interval, spontaneous type 1 Brugada pattern in the prepubescent age and familiar history of sudden death.

Resumo A heterozigose composta é descrita em arritmias hereditárias, geralmente associada a um fenótipo mais grave. Relatos dessa ocorrência em pacientes com síndrome de Brugada ainda são raros. Neste estudo, descrevemos o caso de uma criança com a combinação de duas novas variantes distintas no gene SCN5A, apresentando disfunção do nó sinusal, flutter e fibrilação atrial, intervalo HV prolongado, padrão tipo 1 espontâneo de Brugada na idade pré-puberal e história familiar de morte súbita.

Would calcium or potassium channels be responsible for cardiac arrest produced by adenosine and ATP in the right atria of Wistar rats?

Autonomic nerves release ATP, which is processed into adenosine in the synaptic cleft. Adenosine and ATP exert a negative chronotropic effect in the heart. This study aims to evaluate adenosine and P2 receptors and cellular signalling in cardiac arrest produced by purines in the heart. Right atria of adult Wistar rats were used to evaluate the effects of adenosine, ATP and CPA (an adenosine A1 receptor agonist), in the presence and absence of DPCPX, an adenosine A1 receptor antagonist. Effects of adenosine A2 and A3 receptors agonists and antagonists were also investigated. Finally, involvement of calcium and potassium channels in these responses was assessed using BayK 8644 and 4-Aminopyridine. Cumulative concentration-effect curves of adenosine and CPA resulted in a negative chronotropic effect culminating in cardiac arrest at 1000µM (adenosine) and 1µM (CPA). Furthermore, ATP produced a negative chronotropic effect at 1-300µM and cardiac arrest at 1000µM in the right atrium. ATPγS (a non-hydrolysable analogue of ATP) reduced chronotropism only. The effects of adenosine, CPA and ATP were inhibited by DPCPX, a selective adenosine A1 receptor antagonist. The selective adenosine A2 and A3 receptors antagonists did not alter the chronotropic response of adenosine. 4-Aminopyridine, a blocker of potassium channels at 10mM, prevented the cardiac arrest produced by adenosine and ATP, while BayK 8644, activator of calcium channels, did not prevent cardiac arrest. Adenosine A1 receptor activation by adenosine and ATP produces cardiac arrest in the right atrium of Wistar rats predominantly through activation of potassium channels.

«Las otras¼ bradicardias / Those "other" bradycardias

La bradicardia es un hallazgo frecuente en el contexto de pacientes hospitalizados. Algunas veces se detecta de manera incidental y se minimizan sus implicaciones clínicas. No obstante, en ocasiones se asocia con la presencia de síntomas o compromiso hemodinámico en los pacientes que ameritan una intervención adicional. La etiología de la bradicardia no siempre es fácil de determinar y no es extraño que se inicien múltiples estudios con el fin de aclarar el porqué de la situación. Los clínicos estamos familiarizados con el efecto farmacológico y los efectos adversos de variados medicamentos que usamos cotidianamente. A pesar de esto, existen múltiples medicamentos con potencial para desarrollar la bradicardia como respuesta a una propiedad farmacológica menos conocida o en relación con efectos adversos infrecuentes, pero sin duda significativos. El objetivo de la presente revisión es repasar las propiedades farmacológicas y el impacto clínico de algunas sustancias que se han relacionado con la bradicardia, más allá de los que todos conocemos, con el fin de orientar las intervenciones a realizar en los pacientes con causas farmacológicas y reversibles de la bradicardia.

Bradycardia is a common finding in the context of hospitalized patients. Sometimes it is incidentally detected and its clinical implications are minimized. But sometimes it is associated with the presence of symptoms or hemodynamic compromise in patients who warrant further intervention. The etiology of the bradycardia is not always easy to determine and it is not surprising that many studies are initiated in order to clarify the reason for the situation. Clinicians are familiar with the pharmacological and adverse effects of various drugs we use every day. Despite this, there are many drugs with potential to develop bradycardia in response to a less known pharmacological properties or effects related to rare but certainly significant effects. The aim of this review is to explain the pharmacological properties and clinical impact of some substances that have been associated with bradycardia, beyond which we all know, in order to target interventions to be performed in patients with pharmacological and reversible causes of bradycardia.

Heat Stroke-Induced Sinoatrial Node Dysfunction.

BACKGROUND: Heat stroke has been associated with stress-induced cardiomyopathy and electrocardiogram ST segment elevation and depression. Laboratory studies with dogs have demonstrated heat stroke-induced sinoatrial node dysfunction in the setting of hyperkalemia. No prior case report has described heat stroke-induced complete sinoatrial node dysfunction that resolved in the emergency department. CASE REPORT: An 87-year-old female presented to the emergency department with heat stroke and severe bradycardia. Initial electrocardiogram demonstrated complete sinoatrial node dysfunction. The bradycardia responded to external cardiac pacing and the sinoatrial node dysfunction resolved with aggressive cooling. Emergency physicians should be aware that heat stroke can cause complete sinoatrial node dysfunction and that this bradydysthrmia can be treated with aggressive cooling.

Conduction system in the swine heart: essential landmarks for gross dissection

Background: The components of the cardiac conduction system (CCS) were discovered almost two centuries and presentedin the diagrammatic forms. This should be due to the diffi culty in distinguishing the CCS from the surrounding cardiactissues and the lack of information concerning the precise landmarks for gross dissection. Furthermore the CCS in pig,the animal regarded as a suitable model for the assessment of catheter based intervention, has not been reported. The aimsof the present study were to demonstrate the gross anatomic architecture of CCS in the swine heart, and to provide thevaluable landmarks for the gross anatomic dissection of the CCS.Materials, Methods & Results: Twenty hearts of adult Large White pigs (Sus Scrofa domesticus) were used. Fifteen heartswere elucidated by gross anatomic dissection. The tissue blocks of the sinoatrial node (SAN) and atrioventricular conduction tissue of the fi ve hearts were prepared for histological investigation by staining with Masson’s trichrome. It was foundhistologically that the cardiac conduction tissues were clearly distinguishable from the surrounding cardiac myocardiumand connective tissue. Moreover, the histological information also navigated the location and anatomical architecture ofthe CCS which provided essential guideline for gross dissection. The SAN was somewhat spindle in shape which embedded in epicardial connective tissue of the terminal sulcus. In some cases, it was quite diffi cult to identifythe SAN, so thesinoatrial node artery was used as a clue. The AVN was an elliptical shaped which situated in subendocardial tissue atapex of the triangle of Koch on the atrial surface of the central fi brous body. The distal extremity of the AVN extended intothe central fi brous body to form the penetrating bundle of His. At the boundary between the membranous and muscularparts of the interventricular septum, the AV bundle of His divided into the right...

Conduction system in the swine heart: essential landmarks for gross dissection

Background: The components of the cardiac conduction system (CCS) were discovered almost two centuries and presentedin the diagrammatic forms. This should be due to the diffi culty in distinguishing the CCS from the surrounding cardiactissues and the lack of information concerning the precise landmarks for gross dissection. Furthermore the CCS in pig,the animal regarded as a suitable model for the assessment of catheter based intervention, has not been reported. The aimsof the present study were to demonstrate the gross anatomic architecture of CCS in the swine heart, and to provide thevaluable landmarks for the gross anatomic dissection of the CCS.Materials, Methods & Results: Twenty hearts of adult Large White pigs (Sus Scrofa domesticus) were used. Fifteen heartswere elucidated by gross anatomic dissection. The tissue blocks of the sinoatrial node (SAN) and atrioventricular conduction tissue of the fi ve hearts were prepared for histological investigation by staining with Massons trichrome. It was foundhistologically that the cardiac conduction tissues were clearly distinguishable from the surrounding cardiac myocardiumand connective tissue. Moreover, the histological information also navigated the location and anatomical architecture ofthe CCS which provided essential guideline for gross dissection. The SAN was somewhat spindle in shape which embedded in epicardial connective tissue of the terminal sulcus. In some cases, it was quite diffi cult to identifythe SAN, so thesinoatrial node artery was used as a clue. The AVN was an elliptical shaped which situated in subendocardial tissue atapex of the triangle of Koch on the atrial surface of the central fi brous body. The distal extremity of the AVN extended intothe central fi brous body to form the penetrating bundle of His. At the boundary between the membranous and muscularparts of the interventricular septum, the AV bundle of His divided into the right...(AU)

Bradicardia y convulsiones: una relación multicausal / Bradycardia and seizures: a multi-causal relationship

La disfunción del nodo sinusal consiste en una alteración en la generación del impulso en el nodo sinusal. Su principal causa es la degeneración fibrosa del tejido sinusal. Los casos asociados a convulsiones son multicausales y se deben a los efectos cardiodepresores de los anticonvulsivantes o de sus diluyentes; así mismo se pueden presentar casos de bradicardia y asistolia inducidos por las descargas epilépticas. Se expone el caso de una paciente con status epiléptico tratada con fenitoína endovenosa, quien recibía previamente carbamazepina y desarrolló disfunción del nodo sinusal considerada como un efecto secundario tóxico de su medicación anticonvulsivante.

Sinus node dysfunction is an alteration in the impulse generation in the sinus node. Its main cause is the fibrous degeneration of the sinus tissue. Cases associated with seizures have multiple causes and are due to the cardio-depressant effects of anticonvulsants or its diluents. Likewise, there may be cases of bradycardia and asystole induced by epileptic discharges. Here is presented the case of a female patient with status epilepticus who was treated with intravenous phenytoin and was previously receiving and developed sinus node dysfunction which was considered as a toxic side effect of her anticonvulsant medication.

Anatomic study of the right coronary artery in pigs: feature review in comparison with the human artery / Estudio anatómico de la arteria coronaria derecha en cerdos: revisión de sus características en comparación con la del humano

A few studies conducted on the morphology of coronary arteries in pigs emphasize the description of its course and number of branches. The objective of this study was to determine the anatomic expression of the right coronary artery (RCA) in pigs of commercial stock. One hundred and fifty eight hearts obtained from pigs destined to sacrifice were studied. The RCA were perfused with polyester resin (Palatal 85 percent and Styrene 15 percent) and then subjected to KOH infusion for 5 minutes to release the subepicardial fat. Diameters were measured and courses were evaluated. Results: The diameter of the RCA in its proximal portion was 3.85 mm (SD 0.75). The right artery of the cone originated from the RCA in 100 specimens (63.3 percent) and from the aorta (third coronary) in 8 specimens (5.1 percent). The posterior interventricular branch (PIB) reached the apex in the majority of the cases (49.3 percent). Its proximal diameter was 2.75 mm (SD 0.61). The sinoatrial node branch (SAB) and the atrioventricular node branch (AVNB) originated from the RCA in 100 percent of the specimens. The diameters of the SAB and AVNB were 1.1 mm (SD 0.30) and 1.16 mm (SD 0.30), respectively. The posterior right diagonal branch was not observed. There is an agreement with most prior studies with respect to both SAB and AVNB emerging from the RCA. Morphometric and qualitative knowledge of the RCA and its branches in pigs is relevant for the design of procedural and hemodynamic models.

Los escasos estudios realizados con relación a la morfología de las arterias coronarias en porcinos enfatizan en descripciones de sus trayectorias y número de ramas. El objetivo del estudio fue determinar la expresión anatómica de la arteria coronaria derecha (ACD) en cerdos de razas comerciales. Fueron estudiados 158 corazones extraídos de cerdos destinados al sacrificio. Las ACD fueron perfundidas con resina poliéster (Palatal 85 por ciento y Estireno15 por ciento) y posteriormente sometidas a infusión de KOH durante 5 minutos para liberar la grasa subepicárdica. Se midieron calibres y evaluaron trayectorias. El calibre de la ACD en su porción proximal fue 3,85 mm (DE 0,75). La arteria derecha del cono se originó de la ACD en 100 especímenes (92,6 por ciento) y de la aorta (tercera coronaria) en 8 (7,4 por ciento). La arteria interventricular posterior (AIP) alcanzó el ápex en la mayoría de los casos (49,3 por ciento.) Su calibre proximal fue 2,75 mm (DE 0,61). La rama del nodo sinusal (RNS) y la rama del nodo atrio ventricular (RNAV) se originaron de la ACD en el 100 por ciento de los especímenes. Los calibres de la RNS y RNAV fueron 1,1 mm (DE 0,30) y 1,16 mm (DE 0,30) respectivamente. No se observó rama posterolateral. Existe concordancia con la mayoría de estudios previos con relación a la emergencia desde la ACD de las ramas RNS y RNAV. El conocimiento morfométrico y cualitativo de la ACD y sus ramas en porcinos, es relevante para el diseño de modelos procedimentales y hemodinámicos.

Variaciones de aa arteria del nodo sinoatrial en población Colombiana / Sino-atrial node artery variation in a sample of the Colombian population

Antecedentes. El conocimiento exacto de la integración anatomofisiológica del sistema de conducción del corazón, es fundamental para la comprender la fisiopatología, el diagnóstico y el manejo de muchas de las complicaciones de la enfermedad coronaria y de las cardiopatías en general. Uno de los aspectos fundamentales, más variable y con mayores repercusiones clínicas corresponde al origen y recorrido de las arterias encargadas de irrigar el nódulo sinoatrial. Objetivo. Determinar el origen, recorrido y distribución de las arterias que irrigan el nódulo sinoatrial en una muestra de población colombiana. Material y métodos. La muestra de análisis fueron 60 bloques cardiopulmonares y digestivos seleccionados a través de muestreo por conveniencia. A estos se les realizó una disección convencional de los genitales para la determinación del sexo y posteriormente se procedió con la disección de las arterias coronarias específicamente de la arteria del nódulo sinoatrial, con el fin de establecer su origen y recorrido. Resultados. Como hallazgo principal se encontró que el origen de la arteria del nódulo sinoatrial en 75% provenía de la coronaria derecha, un 15% procedía de la arteria circunfleja y el 10% restante fue codominante. En cuanto al trayecto 86,6% fueron lineales, mientras 13,4% tuvieron formas alternas como Y, doble Y o en tridente. Conclusiones. Se evidenció predominio del origen de la arteria del nódulo sinoatrial en la coronaria derecha, hallazgo coincidente con investigaciones similares e independiente de la procedencia geográfica y el origen racial. Sin embargo, en este estudio se evidenciaron recorridos no reportados en la literatura como la distribución en Y, en doble Y, en K invertida y en tridente.

Background. Accurate knowledge regarding the cardiac conduction system's anatomical-physiological integration is essential for understanding the pathophysiology, diagnosis and management of many complications regarding coronary disease and heart disease in general. One of the more variable fundamental aspects, having the greatest clinical impact, concerns the origin and course of arteries irrigating the sino-atrial node (SAN). Objective. Determining the origin, course and distribution of arteries supplying the SAN in a sample of the Colombian population. Materials and methods. 60 cardiopulmonary and digestive blocks were taken by convenience sampling. Conventional dissection of the genitalia determined gender; the coronary artery was then dissected, specifically the SAN, to establish origin and route. Results. It was found that 75% of the SAN artery's blood supply came from the right coronary artery (RCA), 15% from the circumflex artery and 10% was co-dominant. 86.6% of courses were linear; 13.4% were Y-shaped or Y-and double trident shaped. Conclusions. The prevalence of SAN artery origin in the RCA in this study was consistent with similar research findings, regardless of geographical and racial origin. However, this study report some courses not previously described in the literature, such as Y-, double Y-, inverted K- and trident-shaped forms.

Right coronary artery anatomy: anatomical and morphometric analysis / Anatomia da artéria coronária direita: análises anatômicas e morfométricas

BACKGROUND: It is necessary knowing the large variability of right coronary (RCA) artery specialty for its implications in surgical procedures and clinic events. This variability is usually related to the length, branches quantity, origin and irrigated territories. OBJECTIVE: To evaluate by direct examination the morphologic expression of RCA in Colombian people. METHODS: RCA were measured in 221 fresh hearts by RCA ostium canalization with polyester synthetic resin that was injected in their branches. RESULTS: The caliber of the RCA proximal segment and at the level of the acute angle of the heart was 3.42 ± 0.66 mm and 2.9 ± 0.50 mm, respectively. It ended between crux cordis and the left margin in 75.6 percent of specimens. Posterior interventricular artery (PIA) reached the inferior third, or the apex, or the anterior interventricular sulcus in 149 (67.4 percent) cases. Sinoatrial node artery (SNA) originated in the right coronary in 134 (60.6 percent) cases, 77 (34.9 percent) from circumflex artery (CxA) and from both in 10 (4.5 percent). Posterior right diagonal artery (PRDA) was noted in 38 (17.2 percent) hearts, but only 6 percent of the sample with long PIA, concomitantly presented the PRDA (P = 0.001). In right dominance SNA were originated from RCA in 54.7 percent and form CxA in 46.3 percent (P = 0.06). CONCLUSIONS: Caliber of the RCA and its branches is lesser than the majority of previous studies, while the PRDA frequency is slightly higher than the reported in literature. Clinical and pathological scenarios by these variations should be taken into account: hemodynamic procedures, cardiac surgery and arrhythmias from coronary occlusive disease.

INTRODUÇÃO: É necessário conhecer a grande variabilidade da artéria coronária direita (ACD), especialmente por suas implicações nos procedimentos cirúrgicos e eventos clínicos. Esta variabilidade está geralmente relacionada à extensão, à quantidade de ramos, à origem e aos territórios irrigados. OBJETIVO: Avaliar por exame direto a expressão morfológica da ACD em sujeitos colombianos. Métodos: As ACD foram medidas em 221 corações frescos pela canalização do óstio da ACD com uma resina de poliéster sintético que foi injetada em seus ramos. RESULTADOS: O calibre do segmento proximal da ACD e ao nível do ângulo agudo do coração foi de 3,42 ± 0,66 mm e 2,9 ± 0,50 mm, respectivamente. A ACD terminou entre a crux cordis e a margem esquerda em 75,6 por cento da amostra. A artéria interventricular posterior (AIP) atingiu o terço inferior, o ápice ou o sulco interventricular anterior em 149 (67,4 por cento) casos. A artéria do nó sinoatrial (ANS) surgiu da artéria coronária direita em 134 (60,6 por cento) casos, 77 (34,9 por cento) da artéria circunflexa (ACx) e de ambas em 10 (4,5 por cento) amostras. A artéria diagonal posterior direita (ADPD) foi observada em 38 (17,2 por cento) corações, mas apenas 6 por cento da amostra com uma AIP longa, apresentaram a ADPD (P=0,001). Em corações com dominância direita, a ANS surgiu da ACD em 54,7 por cento e da ACx em 46,3 por cento dos casos (P=0,06). CONCLUSÕES: O calibre da ACD e seus ramos é menor do que o relatado na maioria de estudos anteriores, enquanto que a frequência da ADPD é ligeiramente superior ao relatado na literatura. Cenários clínicos e patológicos por estas variações devem ser levados em conta: procedimentos de hemodinâmica, cirurgia cardíaca e arritmias de doença coronária obstrutiva.

Características morfológicas y posibles implicaciones clínicas de las arterias nodales / Morphological characteristics and potential clinical implications of nodal arteries

La expresión morfológica de las arterias nodales es relevante en el diagnóstico y manejo de eventos clínicos y en abordajes quirúrgicos del corazón. Se estudiaron 88 arterias nodales de corazones obtenidos como material de autopsia. Las arterias coronarias se inyectaron con resina poliéster pigmentada de color rojo. Se registraron las formas de presentación de las arterias nodales y sus características morfométricas. La arteria del nodo sinoatrial se originó de la coronaria derecha en 52 casos (59,1 porcentaje), de la circunfleja en 33 corazones (37,35 porcentaje) y de ambas en 3 (3,4 porcentaje). Su calibre proximal fue de 1,31 mm (más o menos 0,3), correspondiente a las arterias originadas de la coronaria derecha de 1,25 mm (más o menos 0,3) mientras que las que se originaron de la arteria circunfleja obtuvieron un calibre de 1,42 mm (más o menos 0,3), siendo esta diferencia significativa (p= 0,01). Se originó con mayor frecuencia en el tercio anteromedial, tanto de la coronaria derecha como de la circunfleja (54,6 porcentaje y 61,2 porcentaje respectivamente). En su segmento final cruzó por delante de la desembocadura de la vena cava superior en la mayoría de los casos (44 porcentaje), mientras que en 22 corazones (24,5 porcentaje) cursó alrededor de la cava. Se observó arteria en forma de ®S¼ en 14 casos (15,9 porcentaje del total de la muestra y 42,4 porcentaje de las originadas de la arteria circunfleja). La arteria del nodo atrioventricular se originó del segmento en ®U¼ invertida de la coronaria derecha, al nivel de la cruz cardiaca, en 81 corazones (92 porcentaje), y presentó un calibre proximal de 1,06 mm (más o menos 0,22). Con relación al calibre y al origen se evidencian hallazgos que coinciden con estudios previos. Se destaca la alta prevalencia de la arteria en forma de ®S¼ y de la trayectoria de la arteria sinoatrial alrededor de la vena cava superior.

The morphological expression of nodal arteries is important in the diagnosis and management of cardiac clinical events and surgical approaches. 88 nodal arteries of hearts obtained from autopsies were studied. Coronary arteries were injected with polyester resin pigmented with red. Morphological and morphometrical characteristics of nodal arteries were registered. The sinoatrial node artery had its origin in the right coronary artery in 52 cases (59,1 percentage), in the circumflex in 33 (37,35 percentage), and in both in 3 (3,4 percentage). Its proximal caliber was 1,31mm (more or less 0,3), corresponding to the arteries originated in the right coronary artery of 1,25 mm (more or less 0,3), while those that originated in the circumflex artery had a caliber of 1,42 mm (more or less 0,3), difference that was significant (p= 0,01). Its origin occurred more frequently in the anteriomedial third of both the right coronary artery and the circumflex artery (54,6 percentage and 61,2 percentage respectively). In its final segment, it crossed in most cases (44 percentage) in front of the cava vein, while in 22 hearts (24,5 percentage) went around the cava vein. In 14 cases the artery had an ®S¼ shape (15,9 percentage of the total sample and 42,4 percentage of those arising from the circumflex artery). The atrioventricular node artery was originated from the segment in inverted ®U¼ of the right coronary artery, at the level of the crux cardia in 81 hearts (92 percentage) and had a proximal caliber of 1,06 mm (more or less 022). In relation to the caliber and origin, the findings are consistent with previous studies. Prevalence of ®S¼ shape artery and trajectory of the sinoatrial artery around the superior cava vein are highlighted.

Origem das artérias dos nós sinoatrial e atrioventricular em população do sul da Índia: um estudo angiográfico / Origin of the sinoatrial and atrioventricular nodal arteries in South Indians: an angiographic study / Origen de las arterias de los nódulos sinusal y atrioventricular en población del Sur de la India: un estudio angiográfico

Fundamento: Estudar o suprimento arterial do sistema condutor e sua correlação com a dominância das artérias coronárias em população do sul da Índia. Objetivo: Determinar angiograficamente as origens da artéria do nó sinoatrial (AnSA) e artéria do nó atrioventricular (AnAV) em indianos.Métodos: O estudo incluiu 300 pacientes consecutivos (114 do sexo feminino e 186 do sexo masculino; idade média, 55 anos), habitantes da região costeira ao sul da Índia, submetidos a cineangiocoronariografia devido a sintomas como dor no peito, angina pectoris ou teste ergométrico positivo. As angiografias incluíram ambas as artérias coronárias (direita e esquerda) em posição oblíqua anterior direita e esquerda. A origem da AnSA e AnAV a partir das artérias coronárias foi observada e correlacionada à dominância arterial. Resultados: O nó SA (sinoatrial) recebeu suprimento pela artéria coronária direita (ACD) em 53% dos casos, pelo ramo circunflexo (Cx) da artéria coronária esquerda (ACE) em 42,66% dos casos, e em 4,33% dos casos esse nó foi irrigado por ambas as artérias coronárias. O nó AV (atrioventricular) também recebeu suprimento sanguíneo com mais frequência da ACD (72,33% dos casos) do que do ramo Cx da ACE (27,66%). Surpreendentemente, em nenhum caso este nó recebeu suprimento de ambas as artérias coronárias. Conclusão: Os resultados do presente estudo podem auxiliar os cirurgiões cardíacos, sobretudo em cirurgias relacionadas a valvopatias, devido à franca proximidade entre os ramos nodais e o complexo valvar.

Background: To study the arterial supply of the conducting system and its correlation with the dominance of the coronary arteries in the South Indian population. Objective: To determine angiographically the origins of the sinoatrial nodal artery (SAna) and atrioventricular nodal artery (AVna) in Indians. Methods: The study included 300 consecutive patients (114 females, 186 males; mean age, 55 years) living in the southern coastal region of India, who underwent coronary angiography either for the symptoms of chest pain, angina pectoris or positive Treadmill Test. The angiograms contained both coronary arteries (right and left) in the right and left anterior oblique position. The origin of SAna and AVna from the coronary arteries was observed and correlated with the arterial dominance.Results: The SA (sinoatrial) node was supplied by the right coronary artery (RCA) in 53% of the cases, by the circumflex (Cx) branch of left coronary artery (LCA) in 42.66%, and by both coronary arteries in 4.33% of cases. The AV (atrioventricular) node was also more often supplied by the RCA (72.33% of cases) than by the Cx branch of the LCA (27.66%), and surprisingly in none of the cases was this node supplied by both coronary arteries. Conclusion: The results of the present study may help cardiac surgeons, particularly in surgeries related to certain valvular disorders, due to the proximity of the nodal branches to the valve complex.

Fundamento: Estudiar el suministro arterial del sistema conductor y su correlación con la dominancia de las arterias coronarias en población del Sur de la India. Objetivo: Determinar angiográficamente los orígenes de la arteria del nódulo sinusal (AnSA) y la arteria del nódulo atrioventricular (AnAV) en indios. Métodos: El estudio incluyó 300 pacientes consecutivos (114 del sexo femenino y 186 del sexo masculino; edad promedio, 55 años), habitantes de la región costera al Sur de la India, sometidos a cineangiocoronariografía debido a síntomas como dolor en el pecho, angina pectoris o test ergométrico positivo. Las angiografías incluyeron ambas arterias coronarias (derecha e izquierda) en posición oblicua anterior derecha e izquierda. El origen de la AnSA y AnAV a partir de las arterias coronarias se observó y se correlacionó con la dominancia arterial. Resultados: El nódulo SA (sinusal) recibió suministro por la arteria coronaria derecha (ACD) en el 53% de los casos, por la rama circunfleja (Cx) de la arteria coronaria izquierda (ACI) en el 42,66% de los casos, y en el 4,33% de los casos este nódulo fue irrigado por ambas arterias coronarias. El nódulo AV (atrioventricular) también recibió suministro sanguíneo con más frecuencia de la ACD (72,33% de los casos) que la rama Cx de la ACI (27,66%). Sorprendentemente, en ningún caso este nódulo recibió suministro de ambas arterias coronarias.Conclusión: Los resultados del presente estudio pueden auxiliar a los cirujanos cardíacos, sobre todo en cirugías relacionadas a valvulopatías, debido a la franca proximidad entre las ramas nodales y el complejo valvular.

Vascularização arterial da região do nó sinoatrial em corações suínos: origem, distribuição e quantificação / Arterial vascularization of the sinoatrial node in swine hearts: origin, distribution and quantification

O nó sinoatrial, por se encontrar topograficamente instalado como componente inicial do sistema de condução, é responsável pela geração dos impulsos nervosos determinantes da contração cardíaca. Estudos relacionados à morfologia do nó, visando conhecer a origem, trajeto e distribuição dos vasos neste tecido são conhecidos, contudo, no que diz respeito a estes aspectos e aos dados quantitativos da irrigação nodal, no que se refere ao comportamento vascular arterial e a densidade vascular arterial desta região, a literatura é escassa. Com este objetivo foram utilizados 30 corações de suínos SRD, sendo 27 injetados com resina vinílica corada, para análise da origem e trajeto da ANSA (artéria do nó sinoatrial) e 3 corações injetados com solução aquosa de carvão coloidal (tinta nanquim) para proceder à análise estereológica. As artérias atriais originaram-se tanto da artéria coronária direita quanto da esquerda, com predominância da primeira (66,66 por cento e 33,33 por cento, respectivamente). Quando originada da coronária direita, a irrigação ocorreu pelo ramo AADAM (artéria atrial direita cranial medial) em 14 casos e pelos ramos AADAI (artéria atrial direita cranial medial) em 2 casos e AADAL (artéria atrial direita cranial lateral) em 2 casos. Em 9 casos (33,33 por cento) originou-se pela artéria coronária esquerda: quatro pelo ramo AASPL (artéria atrial esquerda caudal lateral), dois pelo ramo AASAI (artéria atrial esquerda cranial intermédia) e três pelo ramo AASAM (artéria atrial esquerda cranial medial). Anastomoses interarteriais, com participação dos vasos responsáveis pela irrigação do território do nó sinoatrial foram observadas na maioria dos casos (25 corações). O Volume do órgão ou Volume Referência (V(ref)) foi de 35,32x10(4)µm³. Para as variáveis estereológicas analisadas, a estimação da densidade de comprimento do vaso (Lv) foi de 766; o comprimento do vaso (L) - mm - foi de 27,06x10(5)µm; a densidade de superfície de área...

The sinoatrial node, for being topographically installed as the initial component of the conduction system, is responsible for the production of the nervous impulses, which determines the cardiac contraction. There have been made studies related to the node's morphology in order to know the origin, distribution and quantification of the vases in this tissue, however, in spite of the results and quantitative data of the nodal irrigation - arterial vascular conduct and arterial vascular density, at the nodal level - the literature is scarce. With this objective 27 SRD swine hearts, injected with colored resin for macroscopic analysis of the origin and distribution of ANSA (sinoatrial node artery), 3 others injected with watery solution of colloidal coal (dyed nanquim) were used, to mark the route of the vases on the node level for stereological analysis. The atrial arteries originated as well from the right coronary artery as from the left one, with predominance of the first (66.66 percent and 33.33 percent, respectively). When originated from the right coronary artery, there existed the following branches: AADAM (right cranial medial atrial artery) in 14 cases, AADAI (right cranial intermedial atrial artery) in 2 cases, and AADAL (right cranial lateral atrial artery) in 2 cases. In 9 cases (33.33 percent) the following branches originated from the left coronary artery: 4 through branch AASPL (left caudal lateral atrial artery), 2 through branch AASAI (left cranial intermedial atrial artery) and 3 through branch AASAM (left cranial medial atrial artery). Interarterial anastomoses with vessels responsible for irrigation of the sinoatrial node area were observed in most of the cases (25 hearts). The Volume or Reference Volume (V(ref)) of the hearts were 35.32x10(4)µm³. For the stereological variables analyzed, the estimate density of the vessel length (Lv) was 766; the vessel length (L) - mm - was 27.06x10(5)µm; the area's surface density...

Contribution to the study of the irrigation of the sinoatrial node in Landrace swines / Contribuição ao estudo da irrigação do nó sinu-atrial em suínos da raça Landrace

The irrigation of the sinoatrial node in Landrace swines was observed in 50 adults animals (25 males and 25 females), raised and slaughtered in the Centro Intraunidade de Zootecnia Industrias Pecuárias "Fernando Costa" (CIZIP) of the Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, Pirassununga, São Paulo. The results obtained allowed us to come to the following conclusions: 1) the portion occupied by the sinoatrial node is more commonly irrigated by collaterals of the ramus circunflexus of the arteria coronaria dextra (94.0% ± 2.8) or by the ones ramus circunflexus dexter (2.0% ± 2.0) , more precisely by the ramus proximalis atrii dextri. They were observed as a single vessel (88.0% ± 4.6) or a double one (8.0% ± 3.8), alone 10 times (20.0% ± 5.7) or associated* 25 times (50.0% ±7.1) with the ramus intermedius atrii dextri, also identified as a single vessel (26.0% ± 6.2) or a double one (24.0% ± 6.0) and, 13 times (26.0% ± 6.2) with the ramus distalis atrii dextri. 2) with less frequency, it is the ramus proximalis atrii sinistri that irrigates the portion occupied by the sinoatrial node, exclusively (2.0% ± 2.0) or associated with the ramus distalis atrii dextri, (2.0% ± 2.0). 3) arterial anastomoses, in which the vessels responsible for the arterial irrigation of the sinoatrial node take part in, were observed in 18 out of the 50 animals observed

A irrigação do nó sinu-atrial em suínos da raça Landrace, foi examinada em 50 corações (25 machos e 25 fêmeas), de animais adultos, criados e abatidos no Centro Intraunidade de Zootecnia e Indústrias Pecuárias "Fernando Costa" (CIZIP) da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, Pirassununga, São Paulo. Os resultados obtidos permitiram-nos chegar as seguintes conclusões: 1) a região ocupada pelo nó-sinu-atrial acha-se irrigada, mais comumente, por colaterais do ramus circunflexus da artéria coronária dextra (94,0% ± 2,8), ou do ramus circunflexus dexter (2,0% ± 2,0), melhor precisando, pelo ramus proximalis atrii dextri; visto como vaso único (88,0% ± 4,6) ou duplo (8,0% ± 3 ,8 ), sozinho 10 vezes (20,0% ± 5,7) ou associado25 vezes (50,0% ± 7,1) ao ramus intermedius atrii dextri, também identificado como vaso simples (26,0% ± 6,2) ou duplo (24,0% ± 6,0) e 13 vezes (26,0% ± 6,2) ao ramus distalis atrii dextri; 2) com menor freqüência, cabe ao ramus proximalis atrii sinistri nutrira região ocupada pelo nó sinu-atrial, exclusivamente 1 vez (2,0% ± 2,0), ou associado ao ramus distaiis atrii dextri, 1 vez (2,0% ± 2,0); 3) anastomoses arteriais, de que participam os vasos responsáveis pela irrigação arterial do nó sinu-atrial, foram registradas em 18 dos 50 corações (36,0% ± 6,8); 4) não existe diferença estatisticamente significante (nível 5,0%) par